Post operative intraperitoneal and pelvic adhesions represent a major problem in patients recovering from abdominal surgery. When organs and tissues in the peritoneal cavity are subject to surgical incision or abrasion, there is a tendency for adhesions to form between the affected areas and neighboring tissue.
In the case of intestinal surgery, the incidence of adhesions causing intestinal obstructions has been reported as approximately four times that due to strangulated hernia. The post operative formation or reformation of pelvic adhesions is reported to be a major factor contributing to the relatively poor results obtained in infertility surgery.
Various methods have been suggested for reducing the instance of peritoneal adhesions following surgical intervention, but results have not been entirely favorable. One method involves the application of chemical treating agents to the site of the surgical incision or abrasion in an effort to inhibit the physiological response responsible for the formation of the fibrous tissue which comprises the adhesion mass. In this category are enzymes such as fibrinolysin and papase, polyphloretinphosphate, oxyphenbutazone, a mixture of phenylbutazone and prednisolone, polyvinylpyrrolidone and dextran.
A second approach to preventing the formation of adhesions is to install a physical barrier material between the site of the surgical activity and the neighboring tissue where adhesions are most expected to occur. In this category are silicone sheets such as Silastic*, a medical grade silicone elastomer available from Dow Corning Gelfilm*, an absorbable gelatin film available from Upjohn, and Surgicel*, a knit fabric of oxidized regenerated cellulose available from Johnson & Johnson Products, Inc.
The results obtained with the prior art materials and methods have varied according to different investigators. In the case of oxidized cellulose, for example, very good results were reported by Larssen, Acta Chir Scand 144: pp. 375-378 (1978) and Raftery, Br. J. Surg. Vol. 67 pp. 57-58 (1980); negative results were obtained by Schroder, Acta Chir Scand 148 pp. 595-596 (1982), Yemini, Int. J. Fertil 29 pp. 194-196 (1984) and Soules, Am. J. Obstet & Gyn, Vol. 143 pp. 829-834 (1982); and mixed results were obtained by Nishimura, Jpn. J. Surg. vol. 13 pp. 159-163 (1983).
The present invention concerns an improved, barrier type material for preventing postoperative adhesions which comprises a fabric of oxidized regenerated cellulose (ORC) having a unique construction which is specifically designed for this application. Current fabrics of ORC are primarily intended for use as absorbable hemostatic materials and function well in this capacity. We have discovered that the efficacy of ORC in preventing peritoneal adhesions is affected by fabric construction, and the fabrics intended for use in hemostasis are not optimum for use as an adhesion barrier.
It is accordingly an object of the present invention to provide an improved adhesion barrier material. It is a further object to provide an improved adhesion barrier fabric comprised of oxidized and regenerated cellulose. It is a yet further object of this invention to provide a knit fabric of ORC having a specific construction which is particularly effective as an adhesion barrier. These and other objectives of the present invention will be apparent from the ensuing description and claims.